1. Field of the Invention
The present invention relates generally to systems for producing apparent 3-dimensional viewing. More particularly, the present invention relates to apparatus useful for projecting and displaying images onto separate projection screens positioned on a single viewing axis in such a manner as to provide audiences with a sensation of 3-dimensional viewing.
2. Description of Related Art
For many decades the motion picture and video display industries have attempted with various degrees of success to provide viewing systems which give a sensation of depth or 3-dimensional viewing to the audience. One early approach involved provided a greater visual depth for viewers and consisted of increasing the projection screen width relative to its height and curving the screen. This provided a viewing area very close to the normal visual range and additionally created increased depth illusion.
Another approach is known as stereoscopic viewing and consists of simultaneously projecting images, photographed at different angles, onto a screen through polarizing filters which are oriented at right angles to each other. Viewers are required to wear a pair of special polarizing viewing spectacles which allows each eye to see only one image. The viewer's brain combines the images so that a resultant image having apparent 3-dimensional characteristics is observed.
Another system for creating 3-dimensional viewing is described in U.S. Pat. No. 2,952,182 and consists of projecting one image on a front screen and projecting a second image on a back screen which is located directly behind the front screen. In order for a viewer to observe the images projected on both screens, the front screen is formed of a wire mesh material which is painted with white pigment on the front, to maximize reflection, and painted black on the back to maximize absorption. The rear screen is a rear projection screen and allows light to pass through it so that it appears to originate from the screen. In order to avoid image "bleed" created by light from the front screen passing through the mesh and reflecting from the rear screen, a filter is positioned between the front and rear screens and at an angle to the front screen. This filter reflects about 80% of the light striking it while allowing sufficient light to pass through so that the viewer can observe the back screen. A real drawback associated with this system is the reduced visualization of the back screen caused by the presence of the filter. That is, only a small percentage of the light originating from the rear screen is transmitted to the viewer opposite the front screen, resulting in low intensity images.
Accordingly, it is an object of the present invention to provide a system for 3-dimensional viewing which does not require viewers to wear stereoscopic viewing spectacles.
It is also an object of the present invention to provide a system for 3-dimensional viewing without image "bleed".
It is further an object of the present invention to provide a system for 3-dimensional viewing which does not require filtering screens.
It is another object of the present invention to provide a system for 3-dimensional viewing which can be constructed economically and easily in motion picture auditoriums having a variety of sizes and dimensions.